Chiropteryx, also known as 'vampire bat', is a supernatural chiropteran species of large vespertiliae that feasts on the blood of the living to sustain itself. Bigger than a human when standing up on its feet with dark, leathery wings that wreathe around its body like a grotesque cloak, these lethal predators glide through the darkness without a hint of sound.

Chiropteryx stand around 7 feet tall from head to feet, with a wingspan of between 20 to 25 feet. Although lesser in bulk than their suspected closest relative, the dire bat, their wings are both larger and faster, and their ability to hunt and kill verges on the supernatural. Despite the size of their wings, they can retract them very close to their bodies midflight to clear narrow spaces without impeding speed or maneuverability.

A vampire bat prefers to hunt with cunning and patience instead of direct confrontation. Easily smart enough to lay ambushes and wise enough to wait for the opportune moments to strike, they dive in to attack their prey when they least suspect it only to immediately disappear again into the darkness afterwards. Exercising this ingrained sense of sadism, chiropteryx like to whittle down their victims' strength in an exhausting game of cat and mice before finally swooping in for the kill.

Using their intelligence, highly honed senses and preditorial instincts, a chiropteryx is more than able of setting traps, often involving blocking off the entrance leading to their lair to ensure that their prey is left at their mercy. From thence on, every bite drains the victim's blood and weakens them bit by bit until the curtain closes.

Most of the time, vampire bats are solitary hunters, but they will occasionally unify under the leadership of a particularly powerful exemplar of their race (usually advanced to at least 15 HD). Such a gathering is often referred to as a conclave. Regardless of their number however, they always hunt alone and will only respond in numbers if the conclave falls under direct attack.

Blood Drain (Su): When a chiropteryx damages a creature with its bite attack, it drains 1d8 points of its Constitution. Blood lost from a chiropteryx bite cannot be naturally replenished, and the wounds from the chiropteryx bite is persistent and cannot be naturally healed (although the hit points lost may be recovered with magic). This is ability drain and is permanent until restored. Creatures that don't have blood (or a Constitution score) are immune to this ability.

Deathwatch (Su): A chiropteryx can determine the physical condition of any living or dead creature or unliving object within the range of its blindsight. This functions as the deathwatch spell, except that the chiropteryx can accurately gauge the amount of health and Constitution any living creature has left. As this ability is supernatural, spells and effects that block magical scrying do not block a chiropteryx' deathwatch ability, but an antimagic field does.

Improved Evasion (Ex): Whenever a chiropteryx is subject to a spell or effect that allows a Reflex save for half damage, it takes no damage on a successful save, and only half damage on a failed save.

Light Weakness (Ex): When exposed to sources of bright light, a chiropteryx may be rebuked or even physically harmed. It takes damage like an undead creature from any damage dealing spell with the Light descriptor and upon exposure to such forces or within the area of a light spell or effect, it becomes sickened and must make a Fortitude save or be nauseated for as long as it remains within the light source.

More than anything, the sun is the chiropteryx' bane. Sunlight deals 2d6 points of damage to it every round, sickening it and requiring it to make a DC 20 Fortitude save to prevent nausea. Furthermore, direct exposure to sunlight suppresses the chiropteryx' damage reduction, greatly weakening it in combat. As such, it only travels overland at night and ventures out during daytime only when sufficient cloud cover is present, or if it has no other choice.

Cantrips such as light and non-magical sources of bright illumination are generally too weak to nauseate a chiropteryx, but they can still sicken it.

Sanguine Bond (Su): Whenever a chiropteryx draws and tastes the blood of a particular creature, it establishes a strong connection to that creature. From the moment of injury onwards, the chiropteryx is completely aware of that creature's condition and location as per the status spell as long as the chiropteryx and the creature are on the same plane of existence. This connection persists even if the chiropteryx' blood drain is countered and restored, and only disappears upon the chiropteryx' death. After tasting particularly tasty blood, a chiropteryx may actively pursue such a surviving victim wherever they go in attempts to gorge upon them once more.